It is well known that a fuel injector has an injection port which is inclined outwardly.
When a valve needle is moved in a valve-opening direction, the fuel is injected into an engine through a fuel-outlet of the injection port.
JP-2013-7316 A (US-2012-0325938 A1) shows a fuel injector in which the fuel is injected outward from a plurality of injection holes provided in an injection hole plate fixed to the valve seat. A seat surface of the valve seat is formed in such a way that the inner diameter thereof decreases in a direction from an upstream side to a downstream side of a flow of the fuel. The injection hole plate has a plurality of concaves at its downstream surface. The injected fuel is separated from the concaves. The fuel is spread in a combustion chamber and its atomization is improved.
However, in the above fuel injector, a center line of each concave and a center line of the injection hole cross each other. A stepped surface is formed between the injection hole and the concave. The stepped surface crosses the center line of the injection hole at acute angle. Thus, the fuel is attracted to the stepped surface. The fuel adhered on the stepped surface may be changed to the fuel deposit, which restricts the atomization of the fuel spray.
Moreover, the fuel flow direction is varied due to the concave. It is difficult to improve a directivity of the fuel spray.